Identification

Description

Sujet(s)

acoustique instrumentale
linear model
wind instruments

Résumé

Based on physical models of musical instruments and of the human voice, a new
generation of sound syntesizers is born: virtual instruments. The models used for
wind-instruments are simple feedback loops in uhich a non-linear sound source
drives a linear,filter representing the pipe of the instrument. While very
rewarding musical sounds have been obtained with these models, it has become
obvious that some essential phenomena escape such a description. In particular
the brightness of the sound generated by trombones is expected to be due to the
essential non-linearity of the wave propagation in the pipe. At fortissimo levels
this leads to shock wave formation observed in our experiments both from
pressure measurements and flow visualization. A modest modification of the
physical model could already take this phenomenon into account. The key idea is
that the non-linear effect is essential for the transfer of sound from the source
towards the listener, but can be ignored in a model of the generation of the pipe
oscillations.